Various embodiments pertain to the art of direct current-to-direct current (DC-DC) power supplies, and more particularly, to over-voltage protection of non-transformer DC-DC power supplies.
Power supplies that convert a high level direct current (DC) input voltage to a low level DC output voltages typically include a means for protecting circuit components during a fault condition (e.g., a short circuit). For example, if a switching component used to drive the voltage converting unit is short circuited to the output, all digital circuits connected to the shorted output can be damaged.
Conventional DC-DC converter power supplies have addressed short circuit concerns by implementing a transformer isolation typology, which uses a transformer and switching element to convert the high voltage input to a low voltage output. Since the primary winding of the transformer is isolated from the secondary winding by an air gap, a shorted switching element will not propagate the higher input voltage onto the lower output voltage. The use of a transformer isolated topology also allows for overvoltage protection of the output by controlling the primary side switching element. However, the transformer circuitry is complex and costly requiring large components to convert the high voltage input to the low voltage output.